(1) Field of the Invention
This invention relates to a method of endoscopic mucosal resection. More particularly it relates to a method of endoscopic mucosal resection performed easily and reliably with assistance of a biocompatible mucopolysaccharide having no anticoagulant activity, and to a local injection preparation used therefor.
(2) Description of the Related Art
Endoscopic mucosal resection (hereinafter abbreviated to "EMR") has been widely accepted as a standard procedure for early-stage neoplastic lesions of gastrointestinal tracts. Recently, various modifications of this EMR technique have been introduced. Currently the accepted EMR techniques include a strip-biopsy method or a lift-and-cut EMR, an endoscopic resection after local injection of saline into the submucosal layer, an endoscopic double-snare polypectomy, an EMR using an over-tube, strip-biopsy using two small-diameter endoscopes, an EMR with a cap-fitted panondoscope, and an EMR using a ligation device.
With the improvements in endoscopic resection techniques, good results have been obtained In terms of local cure and long-term outcome after resection. However, these methods still have technical limitations. For example, the strip-biopsy method requires a two-channeled endoscope and it is not suitable for lesions located on the lesser curvature, posterior wall, and cardia of the stomach. With methods using a translucent cap or a ligation device, the size of the resectable mucosa is limited depending upon the size of the device. Further, the endoscopic view is lost by "red-out" while trapping a lesion in these devices. The EMR using an over-tube as well as the strip-biopsy using two-small diameter endoscopes are cumbersome.
In an EMR technique, an affected mucosal tissue is observed with an endoscope and trapped by a snare to perform resection. The affected mucosal tissue does not protrude to a great extent and the surface of mucosa is slippery. Therefore EMR is usually accompanied by technical difficulties, namely, complete removal of the affected mucosa tissue is difficult to attain and complication such as bleeding or perforation sometimes occurs due to unsuccessful operation. To cope with the difficulties, an improved endoscopic resection technique has been proposed wherein endoscopic resection is performed after local injection of normal saline into the submucosal layer of an affected mucosa tissue. However, a problem arises in that the injected saline diffuses quickly with consequent disappearance of the protrusion.
Another proposal has been made wherein hypertonic saline-epinephrine (HSE) or 504 glucose is used as an alternative to the normal saline for preventing or minimizing bleeding during BMR [Hirao M, Masuda K, Asanuma T. Naka H. Noda K, Matsuura K, et al, Endoscopic resection of early gastric cancer and other tumors with local injection of hypertonic saline-epinephrine, Gastrointest Endosc, 1988, 34:264-9; and Makuuch H, Mitomi H, Machimura T, Mizutani S, Shimada H, Sugano K, et al, Endoscopic mucosal resection for early esophageal cancer by the EEMR-tube method, Stomach Intent., 1993;28:153-9]. This proposal still has a problem such that the injected HSE solution or HSE solution containing 50% glucose is emitted from an opening of the mucosa tissue when incised by a needle knife, with consequent disappearance of the protrusion. Further, the hypertonic saline has a histoaffective effect and the problem of complication of bleeding and/or perforation is not solved.